1. Technical Field
The present disclosure generally relates to printed circuit boards (PCBs), and particularly relates to manufacturing of printed circuit boards and a method for manufacturing the printed circuit board.
2. Description of Related Art
To accommodate development of miniaturized electronic products with multiple functions, printed circuit boards are widely used.
A PCB needs a plurality of conductive vias for electrically connected two or more trace layers. In a method of manufacturing the PCB, firstly, a through hole is defined in a substrate. The substrate includes a dielectric layer, a first copper foil layer and a second copper foil layer. Secondly, a conductive via is formed in the though hole. Thirdly, a first trace layer and a second trace layer are formed on two opposite surfaces of the dielectric layer. Fourthly, an insulating layer is laminated on the second trace layer, and a blind hole is formed in the insulating layer. The conductive via is exposed in the blind hole. As the blind hole must be aligned with the conductive via, when forming the second trace layer, a hole ring surrounding the through hole is formed in the second trace layer. The outer diameter of the hole ring is larger that the diameter of the through hole. Accordingly, a distribution density of the traces in the second trace layer is smaller. Furthermore, as a process of forming the conductive via and a process of forming a plated through hole are different, the cost of manufacturing the printed circuit board is high.
What is needed therefore is a printed circuit board, and a method for manufacturing the printed circuit board to overcome the described limitations.